.header {
    width: 100%;
}

.header input {
    width: 100%;
    height: 30px;
    padding: 0 10px;
    border-radius: 5px;
    box-shadow: 0 0 8px #ccc;
    outline: none;
    border: none;
}

.header input:focus {
    border: none;
    outline: none;
}